If they are street miles, no matter how hard the rider rides, it won't even begin to matter until 50k or more. If the bike has been heavily stunted, crashed multiple times, fixed up halfway, 5k might be a lot.
I put about 24k race track miles, and another 8k on the street on my Honda 929, and it still runs very well. After all that, it has lost a little of it's power, but you'd only notice on the track. I still have the bike, since it's not worth what I'd get by selling it. I'd be very happy to have it, and I still enjoy riding it from time to time, even though I have newer bikes as well.